My thoughts and findings regarding Pyrrosia subfurfuracea and Pyrrosia calvata

A few years back I came across a Pyrrosia in a Cornish nursery labelled ‘collected in Kashmir’—it was one I had not seen before. It was a great looking fern and I was able to acquire a division. As with all ‘unnamed’ plants, it’s nice to try and work out what you’re growing. So I sent a picture of it to a few friends and, although there were a few initial thoughts, they also didn’t really know what it was.

Last spring, I sent a piece of this fern to Dick Hayward. Dick wasn’t too sure what it was either, so he took some photos of this plant and sent them to Christopher Fraser-Jenkins. Although I don’t know Christopher myself, as we know, he is the authority on the ferns of India, Pakistan, Kashmir, Nepal, Bhutan and so on. Christopher’s response was that he thought this fern was Pyrrosia subfurfuracea and the fern we have in the UK with the name P. subfurfuracea wasn’t a fern he had seen before. It seems quite a few plantspeople around the UK had been thinking the fern we had been previously calling P. subfurfuracea in the UK was actually P. calvata. The fern previously circulating as P. subfurfuracea was brought to the UK by Tom Hudson, owner of Tregrehan Garden in Cornwall, and was collected in Vietnam growing on karst. I’m assuming that no one else has collected it and brought it to the UK. All the people who have acquired this plant over the years have seemingly got it from Tom or from someone who got theirs

from him. Since its introduction, it has been named P. subfurfuracea. Tom said that

Tim Pyner was his go to man with regards to fern names and that Tim was happy with the identification of P. subfurfuracea, so that was the name that stuck. It is worth noting that Peter Hovenkamp put together a monograph of Pyrrosia in 1986 and that he synonymises Polypodium calvatum (an earlier name for Pyrrosia calvata) with P. subfurfuracea.

According to the Flora of China website, www.efloras.org, the description of P. subfurfuracea doesn’t seem to match with the plant that has been in

cultivation in the UK with this name. The lamina length is given as 45–60 cm and width as 6.5–11 cm. Our fern tends to have a much narrower frond. The Flora of China website gives the lamina length and width for P. calvata as 25–60 cm and 2.5–5 cm respectively. This seems to match with the plant we have in circulation under the name of P. subfurfuracea, thus adding to the growing consensus that it is P. calvata.

Getting back to the ‘collected in Kashmir’ Pyrrosia, as mentioned, Christopher Fraser-Jenkins thought this to be P. subfurfuracea. The Flora of China information on P. subfurfuracea also certainly shows lamina dimensions which are closely matched to this fern. In Diego Taveres’ paper, ’The Felt Fern Genus Pyrrosia (Polypodiaceae): a New Subgeneric Classification with a Molecular Phylogenic Analysis Based on Three Plastid

Markers’ (Acta Phytotaxonomica et Geobotanica, 68:2, 2017), Figure 3 shows pictures of a plant called P. subfurfuracea. From my perspective, and having this plant in front of me, this is the same plant as the Pyrrosia ‘collected in Kashmir’, found at the Cornish nursery. So from this article, the Flora of China website and Christopher Fraser-

Jenkins thoughts, I am left with the view that this Pyrrosia is the true P. subfurfuracea.

With regards to the Kashmir fern, measured from the bottom of the stipe to the top of the lamina, I have a frond measuring 14 cm wide and 74 cm long. Other fronds are of similar dimensions but a bit smaller and close to the Flora of China description of P. subfurfuracea. I have also been growing mine in full shade and feeding it regularly, which might explain the bigger leaves. With regards to our potential P. calvata,

the frond dimensions are quite different to this, with much narrower lamina.

A slight anomaly is that according to most sources the distribution for P. subfurfuracea is wide: China, Tibet, India, Myanmar, Thailand and so on. Whereas the ‘published’ range of P. calvata is shown as just China. Our previously named P. subfurfuracea was collected in Vietnam, which borders China to the north. I have found a reference to P. calvata existing in Vietnam—in fact it even has a Vietnamese name, Ráng tai chuột canva.

As much as I like to know names of plants and what I’m growing, I’m very happy growing both of these beautiful Pyrrosia whether I have full clarity on names or not. They are great species and a joy to grow!

EVAN SHARP

Evan grows a number of ferns in his small South London garden. With a love for woodland plants, particularly Araliaceae, and other evergreens from around the world. He is a gardener by trade and works in the London area. Favoured ferns include Pyrrosia, Lepisorus and Microsorum.